1. Field: This invention relates to gripping or extracting tools. More particularly, the invention is directed to an extractor tool adapted for use in retrieving objects from spatially restricted environments.
2. State of the Art: In many scientific and industrial processes, a worker must handle objects by remote control means. These means may be necessitated by the object to be grasped being positioned within a spatially restricted environment, precluding direct contact between the worker and the object. Alternatively, the object may contain potentially dangerous toxic material, which could be dangerous to a worker contacting the object.
One example of an object confined within a spatially restricted area is a broken torsion bar on a tracked all-terrain vehicle. Torsion bars in such all-terrain vehicles occasionally break. These torsion bars run laterally from one side of the vehicle to the other. On one side of the vehicle, they are splined into contact with the vehicle's frame. On the other side of the vehicle, they mechanically cooperate with the tracked road wheel.
In part due to the great weight of such vehicles and the rugged terrain over which they typically travel, the torsion bars on these vehicles are subjected to high levels of stress. Occasionally, a torsion bar breaks, thus disabling or greatly hindering the maneuverability of the vehicle.
Present methods for removing broken torsion bars are technically complicated and time consuming. Although one portion of a broken torsion bar is relatively easily removed from the vehicle with the use of a puller-type device, another portion of the bar remains splined with the vehicle in a relatively inaccessible location. The only physical access to the remaining broken portion is through the splined socket of the road wheel arm from which the first portion of the broken torsion bar has been removed. This socket is typically only 2.180 inches in diameter.
In the conventional repair approach, the track of the vehicle is disassembled and removed. The road wheels and the torsion bar bolt are then removed. A device known as a "slam hammer" puller is then used to remove the first portion of the broken torsion bar. A long welding rod is then arc welded onto the portion of the torsion bar remaining in the vehicle. This is done through the splined socket in the road wheel arm. Once the welding rod is affixed to the broken bar portion, the rod, together with the bar, is extracted from the vehicle by pulling on the rod.
This conventional method has not been very acceptable. The arc welding required by this method must be performed in a spatially restricted environment which not only increases the difficulty of the welding operation, but also increases the likelihood of the welding rod inadvertently arcing to an adjacent unbroken torsion bar or other part of the vehicle. When the welding rod does inadvertently arc, it creates a welding spot on the adjacent torsion bar. This welding spot functions as a stress raiser thereby seriously weakening the adjacent torsion bar. As a result, the structural integrity of the bar may be impacted, contributing to a shortened wear life. Furthermore, the heat generated by the welding creates the possibility of igniting flammable liquids either within or in the vicinity of the vehicle.
If the conventional arc welding method is unsuccessful in removing the remaining portion of the broken torsion bar, another more complicated method is utilized. In this method, the entire engine or "power pack" and fuel tanks are removed from the tank, or other tracked vehicle, in order to gain access to the retaining portion of the torsion bar. This method requires several people and many man-hours for its completion. Understandably, these manpower and time requirements may be unacceptable repair situations under battlefield conditions.
A need exists for a simple method or tool for removing the remaining portion of broken torsion bars from tanks and other tracked vehicles. Ideally the tool would be portable, adaptable to different situations, sturdy, and not incorporate the use of a spark or flame.
Various remote control handling apparatus, grasping or gripping tools as they are more commonly known, have been suggested. Among those devices are the following:
U.S. Pat. No. 4,646,241 (Nebelung) discloses a take-out mechanism for removing containers from a mold. The mechanism comprises a centering member and movable gripping jaw-like members for grasping the containers for removal.
U.S. Pat. No. 4,583,275 (Diaz) discloses a transmission direct clutch removing and installing tool for use with motor vehicles having a General Motors Corporation Turbo-Hydromatic 400 automatic transmission. The tool has a T-shaped operating handle and a rod.
U.S. Pat. No. 4,377,956 (Cooper) discloses a pipe extractor tool for use in removing broken pipe sections which require unthreading from another section. The tool comprises a hollow shank, a push rod inserted through the hollow shank, cams placed on the end of the push rod, and a T-shaped handle. The cams have edges for contacting the broken pipe section, and may be spring-loaded.
U.S. Pat. No. 4,121,868 (Pierce) discloses a cam actuated pivotal jaw gripping apparatus for lifting irregularly-shaped objects remotely. The apparatus has gripping arms pivotally mounted to its cover.
U.S. Pat. No. 3,316,780 (Herkner) discloses a broken rifle shell extractor having a stepped spindle having a rearward segment of enlarged diameter and a forward segment of lesser diameter. Wedge means are positioned on the forward segment of the spindle.
U.S. Pat. No. 3,219,376 (Peters) discloses a remote control article handling tool having gripping jaws, a rod, guide cylinder for actuating the jaws, and an elongated tube.
U.S. Pat. No. 2,699,478 (Bowie) discloses a bulb changing device having opposed jaw members which are actuated remotely and which can be extended to enable the user to reach lamp fixtures in difficult or remote positions.
U.S. Pat. No. 2,555,381 (Thisse) discloses a device for inserting and extracting metal radio tubes, and comprises a body having slidable semi-cylindrical gripping members for grasping vacuum tubes.
U.S. Pat. No. 1,761,463 (Beckett) discloses an extraction tool for removing obstructions, broken or lost parts of rotary bits, and other tools used in rotary drilling from a well. The tool has gripping jaws actuated by moving the jaws relative to a shoe or housing.